Multiple DB writers, good or bad (in my case)?

Hi All,
Oracle v11.2 on Linux 64 bit.
I have a production database which is bigger SGA (25GB) + more CPUs (32) then a testing database (12GB SGA + 8 CPUs). But we get more I/O waits (and performance issues) on the production database then the testing database. And both databases process similar amount of data.
After lot of discussions, people looking after the SAN are saying, there are issues with the SAN configuration (probably the disks are shared with other very busy database).
In this situation i.e. when I/O system is not fast enough or overused, having more database writers can be a problem? or not?
The testing database I mentioned above has only 1 db writer, db_writer_processes=1.
The production database has, db_writer_processes=8.
Can multiple db writer processes cause contention?
Thanks in advance

It depends what you mean by contention, assuming you are using a filesystem that supports async io and is mounted direct then having 8 db writers should not cause any additional io contention, it may however cause an increase in cpu usage and contention as you have 8 processes doing work that it may be possible to handle with a single process. In your case the team supporting the SAN have identified a bottleneck/performance problem this is what needs to be addressed having 1 or 8 db writers is unlikely to change the total amount of IO that needs to be performed by a significant factor. Before looking at disk layouts, adding solid state drives or other storage voodoo Make sure you know exactly where the bottleneck is as upgrading the drives on a san thats bottlenecked by the fibre channel switches is expensive and embarrassing.
Generally speaking when configuring a new system I use a single db_writer unless we have encountered a performance problem during testing that can be fixed with multiple db writers, one exception to this is for systems with numa optimisation where we start at one db writer per numa zone even this is questionable in most cases but it saves arguing with our developers who really want one db writer per cpu (as they subscribe to the more is better theory of database parameters!)
(on a less serious note where did you find a SAN administrator that would ever admit to a performance issue with their storage? and can I borrow them.)
Chris

Similar Messages

  • Placing a PDF file in an InDesign Doc and PDF again for a vendor- Good or Bad?

    Current debate in the graphics department is
    Is it good or bad to place a PDF (general Press Quality) into an InDesign document and then creating a new PDF file with print vendor settings from that document?
    My thought is that you in some cases are double compressing, lower dpi images getting compressed, RGB color mode images okay on layout but now are converted to CMYK and shift in the PDF.
    Are there other issues and if so what are they.
    Also is there an easy way to check ppi, color mode and compression of an acrobat PDF? I mean other than doing a preflight and searching into each image folder twenty levels deep. FlightCheck and Enfocus are not options,
    too many vendors and not enough time.
    Thank you all in advance for your words of wisdom.

    Dov, I just got off the phone with a trusted professional in the Prepress field at a quite reputable print house, and he said "Dov is the guru of PDFs, ask him this...Will the InDesign CS3 preflight see the characteristics of a PDF (color mode, dpi(ppi), compression) if the original placed PDF is created as a pdf .X4 (1.7)? Ask him also if you were to use one form of compression (say lossless) in the original PDF, and then another form(say lossy) in the vendor PDF would it hold both or convert the first PDF compression to the second form?"
    Any other responses are also welcomed.

  • HT2105 When you get a apple receipt for itunes songs and you paid with a itunes gift card do they charge you or give you store credit what's store credit is it good or bad or does it charge you if you have a free account with no credit cards at all is it

    When you get a apple receipt for itunes songs and you paid with a itunes gift card do they charge you or give you store credit what's store credit is it good or bad or does it charge you if you have a free account with no credit cards at all is it bad?

    iTunes credits are, for example, if you download a song from the store and it's found to be corrupt - if the track can't be fixed then iTunes support will tend to give you a song credit for a free download.
    When you purchase music from the store then any credits that you have will be used first, then any balance that you have (e.g. from iTunes gift cards or allowances), and any remaining amount will be taken from your credit card.

  • Goods and Bads with the 6110 Navigator

    Hi
    New user of this forum and a proud owner of a Nokia 6110 Navigator. I had the 6280 but after 2 SW upgrades and still problem with it, I gave up.
    First impression of the 6110 is good, but I found a couple of small things that ”irritates” me.
    1 – The timer function when you write “0200” and press options instead of green (call) button.
    2 – The original headset is too cheap to be an expensive phone like this, should be more like Koss “plug-in-your-ear” kind of headphones, instead of the small “put-close-to-your-ear” thing that is included.
    Also, the straight up cable from the top of the phone is no good. Makes the phone lie bad in the pocket. I also guessing that this cable is going to snap after a while. Why not a 90 degree “adapter” or something?
    3 – When you sending an SMS, on my 6280 you could choose “last used number” or something like that, now you have to choose name, and then number, and then OK to go back to the SMS.
    Well.. that’s it so far. Anyone else have goods and bads about this phone ?
    mvh / regards
    Timmy

    hi im havin same issues!!
    i went from 6280 to 6110 after i smashed it
    1.first off i didnt kno of the timer option...good bcoz it was annoyin not havin a stopwatch
    2. that "recent use list"...lack of it...is annoying. i just made groups of ppl i msg most
    3. menu organisation is confusing
    4. in call history, it only shows most recent time for that entry, ven if they rang 5 times that day, also they dont show call long eg duration of 3mins 40secs
    5. on my 6280, i had a shortcut menu as mi left select button, cant do this now
    6. power button is end call button, lotsa accidental turn offs
    7. cant turn off start up tone
    oh well i still like it

  • Is this good or bad in terms of battery life?

    So I have a question, my usage is 1 hour, 11 minutes; standby is 13 hours, 29 minutes. This is since the last full charge on my iphone4s and now the battery is at 68%. Is this good or bad, and the thing is when I used certain apps like words with friends even for 2-3mins I actually noticed the battery life going down 2%, and I know that because I have the option for showing the battery percentage switched to on. It's frustating that I'm doing the simplest task like going through settings and the battery is draining so quickly. Does anyone have and suggestions about increasing the battery life?

    The short battery life is an issue of iOS5 that should be fixed with the next updates. ( also hope that Apple would fix it fast)

  • What is a good download broadband speed. Mine is 4.17mb/s. Is that good or bad?

    What is a good download speed. Mine is 4.17mb/s is this good or bad?

    It's average. Do you have cable or DSL? I'm moving into an apartment that has cable speeds of up to 20 megabits per second. Cable speeds do vary and, at the low end, run around 5 megabits per second.
    So - cable or DSL. If cable, call your local ISP and see if they have a package with higher Internet speeds.
    Clinton

  • Clean my mac, is it good or bad

    Hi, I have seen the software clean my mac some say it's good, some say it's bad, can you tell me if it's good or bad, thanks.

    In regards to keeping your Mac happy... have a look at these Links...
    http://support.apple.com/kb/HT1147
    http://www.thexlab.com/faqs/maintainingmacosx.html

  • Updating iphone3 is it good or bad?

    updating iphone3 is it good or bad?

    updates are always good. you should always update as soon as you have an update available.

  • Panasonic AG-DVX100b good or bad?

    Hey guys ok so i have tons of problems with my canon gl2... anyone out there DONT GET IT!! if your going with fcp for all i know 1. dropped frame rates alllll the time look at other peoples comments its true! 2. myn has a rewind issue.... its really annoying. Anyway thats not what im here for i am thinking of sellign my canon gl2 and getting a Panasonic AG-DVX100b since everyone says it works great with fcp 6 can you give a good or bad? tell me whats good about it whats bad... any info i should know... and if it works good with Final Cut Pro 6... i hope you help me out if you need this im on a macbook pro with final cut pro 6.0 and its a panasonic ag-dvx100b i hop that covers it!

    Of course you find only ISSUES when you search the forums for the GL2...who posts that they are having success? No one walks into a doctor's office and says, "My arms feel really good, and my lungs are clear." No, they go to the doctor's office saying "I am having trouble breathing, and I broke my arm."
    If you search the forums, you see plenty of posts with people having issues with DVX cameras too. Especially the forum dedicated to that camera. True, Canon cameras are a bit more finicky, but they work fine. Some have issues, others do not.
    Shane

  • Migrating assistant good or bad

    Hi guys...
    This is my first post so be gentle... I just have a small question for you guys and girls... what is your view on the migrating assistant, is it good or bad... i have heard someone saying that it migrates some files over that mess up your system... and if it does how do i know which to delete.. and second of all can you choose exactely what to bring over or does it just take everything... is targetdisk mode a better option... maybe a bit more timeconsuming but safer...?? Please give me your opinions... Thanks... ohh forgot to say, reason why im asking is that im planning on buying the infamous MBP..
      Mac OS X (10.4.6)  
    ibook g4 1.33   Mac OS X (10.4.6)   Really want MBP

    I would say that this is a WARNING [capital letters - if you can't tell already ;- ) ]
    My friend - who is a computer tech [Mac & PC] since the Apple II days. For all of you that don't know - that is 30 years ago. He bought his first BRAND NEW computer ever - yesterday - A MacBook Pro 2.16 w/ 7200RPM HD [off the shelf at a local Apple store]. He has made a LOT of money from repairing computers - he didn't have to buy this MacBook, because he has EVERYTHING else - he bought it because the MBP represented the ability to have the Mac OS + WIN XP on the same machine. And also - his clients were asking questions about the MBP, and he had to know - first hand, what they were about.
    He used the migration assistant to transfer his files from his PowerBook G4 - 17" [1.67MHz] - and there was disasterous consequences! After the transfer - the new MBP wouldn't boot to the desktop - until several restarts later. Finally when he could - there was some very weird stuff going on.
    1. No Airport recoginition
    2. Screen stayed on full bright [couldn't be dimmed]
    3. His BlueTooth cellphone would shut off [I know - this is crazy - but it is true, the MBP somehow killed the cellphone connection!]
    4. Kernel panics - [many]
    He [with 30 years experience] promptly returned the MBP to the Apple store - and showed it to the "Genius" - who immediately gave him a brand new one.
    He [or the "genius"] never had any reason to doubt the "integrity" of the "Migration Assistant". My friend thought that his MBP was defective - and the Apple "Genius" thought the same thing.
    So - he took it [the new one] home - and used the "Migration Assistant" again - and the exact same thing happened!
    Finally - he just decided to re-install the whole operating system [clean install] - and now everything is fine.
    If I were you - I wouldn't trust the "Migration Assistant".
    PM G5 1.8 SP REV A   Mac OS X (10.4.2)  

  • Good or bad battery???

    hi
    i just bought a macbook pro 15" last week and im just wondering if i have a good or bad battery 'coz upon opening my macbook for the first time it suggested a lot of updates, including the battery update...so i did all updates...
    i charged my macbook fully last night and used it this morning...i checked my battery status and says 99%-2:55 remaining...then after 97%-4:11 remaining...
    i also check preferences....
    full charge capacity : 5489
    remaining capacity : 5407
    amperage : -1496
    voltage : 12294
    cycle count : 3
    i hope someone can enlighten me...
    thanks in advance...
    macbookpro Mac OS X (10.4.9)
    macbookpro   Mac OS X (10.4.9)  

    your stats seem ok.. i've gotten it as high as 142 hours temporarily, when its discharging.. the battery time to die measurement is at best an estimate..
    what were you running that you were drawing -1400 amps? thats a bit excessive...
    i run a problem called IBatt2 it has a grading system which compares your battery to the median of the same type of system battery... it will also show you the essential data...
    my battery with 45 cycles, gets a "C" grade on their system.
    MBP C2D 15.4" 2.33ghz, 2gb Ram, 120gb HD.   Mac OS X (10.4.9)  

  • Non-numeric primary is good or bad for design

    In general, the primary key created using the non-numeric key is good or bad ?  Any specific reason?

    Numeric datatype is good for primary key because :
    1.No need to implicit conversion
    2.NO overhead in using a NUMBER datatype in joins!!
    3.Auto primary key index will be used since there is no conversion require for numeric datatype.
    All I learn and came to know from Sybrand's reply at below link:
    optimum datatype for primary key column O9i - Oracle Database
    Regards
    Girish Sharma

  • IPod touch - IS IT GOOD OR BAD?????

    i have just bought an ipod touch and my personal view is excellent!
    98% works perfectly - just the safari web brouser can be slow (eventhough im on highspeed wireless broadband)
    i love the coverflow and scrolling is amazing with a flick of a finger
    buying on the move is a big bonus - i've just been to scotland and was in a wifi area and bought a couple of songs! it only takes seconds aswell!
    pictures are clear and easy to see and zooming in by 'pinching' is clever and works well.
    obviously videos are good and so is music!!!!
    thats what i think about the Ipod touch what about you - please leave your comments on it - good or bad..............

    What I have found disappointing so far is web access on the ipod touch: I have not been able to log on to any commercial network (= requiring some sort of authentication) for example in hotels. It seems that Safari on the ipod touch does not support certain functions required. The connections worked flawlessly from Safari on my Macbook so it seem to be a ipod touch issue (I assume the same goes for the iphone).

  • Battery life good or bad, confused

    is this good battery life or not? .... my friends tell me its bad
    ive been using my phone for 2 hours and 24 min and its at 64%
    with 4 hours and 7 min of standby
    is this good or bad or is it normal usage?

    Well that seems fine then because phone calls do drain the battery faster, along with streaming media off youtube. I think your friends are wrong

  • Using a power bank good or bad for iphone battery lifespan?

    I currently use iphone 5, i see many aid product made now such as power bank,
    but a question comes in my mind , is that good or bad for our battery lifespan?

    Are you referring to cases with battery packs in them?
    If so, most have a switch to turn the battery in the case on or off.
    Having the iPhone or any phone in a battery case is neither good or bad.  It is merely a way to extend the "life" of the device between charges without the need to physically plug the device in as there is always the extra battery onboard.

Maybe you are looking for

  • Trouble Updating Air on Windows XP

    ANY HELP IS GREATLY APPRECIATED ! I have windows XP Media center.   My previous version of Air is 1.0  I have logs from the installation as well as MSI logs Here are the Install logs: [2011-09-28:11:10:39] Runtime Installer begin with version 2.7.1.1

  • Error Message on 7520 All In One Set up on MAC

    I have tried several times to install the drivers for the HP 7520 on my MAC (10.9.5 Mavericks).  Each time I get this error message; The system extension "/System/Library/Extensions/AppleUSBEthernetHost.kext" was installed improperly and cannot be us

  • Dsiplay Dynamic Column in ALV Grid

    Hellow everyone, i am using alv grid to display the stock in detail , I need date and stock qnty with labour hour dynamic , my requriend output is:                             LVside                                 HV side                      Coresi

  • Apple TV mirror reverts back to iPad

    Apple TV mirror reverts back to iPad every few minutes. Is there a fix?

  • Regarding MM details

    hi experts, I am new to MM. so any one give idea and materials about Mm and also give useful tips to know what is what about it. Thanks in advance, Regards Vignesh.s